Many years ago I was told of a clergy colleague whose sermon for Trinity Sunday consisted of just six words. I have no idea whether this was just an idea or an actual preached sermon. The six words were:

"Brothers and sisters, it's a mystery."

God as Trinity, the Father, Son and Holy Spirit or Creator, Redeemer and Giver of Life or Three Persons in One Being is indeed 'a mystery.'

But the mystery of the Triune God of Christian belief and worship should not be the mystery of mathematics (how can God be three yet one?) nor of illustrations (is a triangle a good image for explaining the Trinity?). It should be the mystery of love. God is love, we are told, twice in 1 John 4.

What does this mean? The answer, the creeds and the doctrines of faith tell us, is not that God is the concept of love but that God is the dynamic of love, Three Persons in One Being, a community of love in which the Father loves the Son, the Son loves the Spirit, the Spirit loves the Father (etc) and in that love there is no division of will nor of status. United in love, Father Son and Spirit work as One to create, redeem and sustain life.

Determined by love to love what that Unity has created, Father Son and Spirit take up three distinct roles so that creation, redemption and sustenance of life take place. In this understanding creation is itself a fruit of the love which is God for that Love seeks to love more rather than less: Father Son and Spirit create a world to love (John 3:16) and in that love draw all people to God that fellowship between Father Son and Spirit might be enlarged to include creatures. specifically being drawn into the fellowship of the Three in One through identity in Christ the Son as the body of Christ. (Key biblical passages on this understanding are John 13-17, 1 John 1-4, Revelation 1-22).

As Trinitarian Christians we are called to bear witness to the Love which is God and to the God who is love.

Proverbs 8:1-4, 22-31

From a Trinitarian perspective, this passage from the Old Testament is important because it presents the wisdom of God as a personification that is, wisdom is presented in these verses in a personal way, as an agent or assistant of God in the acts of creation. In doing this a seed is planted in ancient theological thinking which grew to include the possibility that not only the 'wisdom' of God, but also 'the word' of God could be personified. When that conceptualization was bound together with reflection on the role of angels, as personal messengers of God sent by God into the world to converse with people, sometimes in a form of such impressiveness that recipients of angelic visitations believed they were in the presence of God, the foundation was laid for a new development. That new development was the recognition by the first Christian theologians (especially John the Evangelist) that the wisdom/word of God was not only able to be written about in terms of personification, the wisdom/word of God had come into the world in a human person, Jesus Christ of Nazareth.

Psalm 8

This psalm can be read in various ways (e.g. as a pearl of praise of great price, one which has justly received the attention of very fine composers) but here we read it in Trinitarian perspective as an address to God about the ordering of the world and the place of humanity in it. Above all is God, within the glory of God we find ourselves inhabiting a marvellous world in which it is amazing that God has remembered us, ordered as we are to a rank below the angels (8:5). Yet God has not just remembered us, God has crowned us with glory and honour and given us dominion over creation (8:5-6).

Thus when we consider God as Trinity we are considering God as God, utterly distinct in rank, status and glory from his creation and from us as his creatures yet also as God who in the Incarnation of Jesus Christ the Son of God has bridged the distinction, becoming one with us.

Romans 5:1-5

Writing these five verses, Paul has not set out to tell us about God as Trinity but, on this Sunday, he does handily write about God's work in salvation including the roles of Jesus Christ and the Holy Spirit. God has sent the Lord Jesus Christ to 'justify' us (through his sacrificial death on the cross, as elucidated in Romans 1-4). As justified sinners we have access to the grace of God (5:2); the grace of God is God's love 'poured into our hearts' (5:5). How does this love reach us as an experience of life rather than a concept in our minds? It is 'through the Holy Spirit' (5:5). Thus the dynamic action of God Father Son and Holy Spirit as the God of our salvation is expressed in this passage, a dynamic action which is 'for us' (further on 'us', 'for us, 'for our sakes' see, among many Pauline texts, Romans 4:23-25).

The giving of the Holy Spirit to us (5:5) means that God's love does more than flow into us (say, like water from a lake, through a pipe, into a bucket). God himself comes to live in us and bind our lives to the life of God itself (so, in an important way, in the image above, we are like the bucket receiving water from a pipe and we are like a bucket dipped into the lake itself). Thus Paul can write in 5:2 of 'our hope of sharing the glory of God.' As members of the body of Christ we share in God's life in Christ.

[Much much more can be said about preaching from this passage, especially from 5:1. These thoughts are specifically geared for Trinity Sunday].

John 16:12-15

In some ways this is a frustratingly short passage from John when the fullness of revelation about the Holy Spirit is given across several Johannine passages (including John 14:25-31; 15:26-27; 16:4b-11).

Nevertheless a vital truth is taught. The Spirit of God is the Spirit of truth. In one way, of course this is true: we would not expect God's Spirit to lie to us. In another way, this is unexpected in the sense that the Spirit of truth 'will guide you [Jesus' disciples] into all the truth' (16:13). Jesus has many things to say but they cannot be said now (16:12). Not to worry because the Spirit of Truth (also known in this gospel as the Advocate / Counsellor / Helper / Paraclete) will guide us to what we need to know from Jesus.

In this sense, as we find sometimes elsewhere in the New Testament, the Holy Spirit is the Spirit of Jesus. The Holy Spirit is trustworthy as faithful servant of Jesus and his mission. Through the Holy Spirit we meet the risen Lord Jesus and from the Holy Spirit we learn what Jesus wishes to teach us.

Does this mean that the Holy Spirit will teach us new information or new insight into what we already know from Jesus?

Some scholarly debate occurs about this. John's Gospel itself may provide a clue and the epistles another clue. In the former we find new insight into what we already know about Jesus from the earlier gospels of Matthew, Mark and Luke. In the latter we find the meaning of the events of Jesus' life being drawn out for us: Christ died on the cross for our salvation. Christ rose from the dead in order that we too may rise with Christ to glory.

We see that the passage rounds off, in 16:15 with talk of God the Father. Jesus has, says, and does nothing except what belongs to, comes from and is directed by the Father. By implication the Spirit of Truth declares only what God the Father has revealed to God the Son. In this way the unity of God is expressed. The diversity of the Godhead is experienced as we meet God in the three persons of Father, Son and Holy Spirit. John, writing these words down, may not have had the advantage we have of knowing how to talk about God as 'Three in One' but he knew that God was One yet experienced as Three Persons working in profound unity.